Saudi Arabia is one of the closest U.S. allies in the Arab world, but it is unclear exactly what approach U.S. officials and diplomats will take in persuading the Saudis to ease the blockade.

Saudi Foreign Minister Adel al-Jubeir told Reuters last month that no country has given more aid to Yemen than Saudi Arabia. But he said none has gone to Houthi-controlled areas of northern Yemen, accusing the rebels of stealing and selling the aid.

The Houthis seized the Yemeni capital of Sana’a in 2014, forcing the internationally recognized government of President Abd-Rabbu Mansour Hadi to flee to Saudi Arabia before returning to the southern port of Aden.

The Saudi airstrikes aimed at forcing out the Houthis have obliterated entire neighborhoods and killed thousands of civilians.

Yemen is also struggling with a cholera outbreak and what the U.N. is warning is a looming famine.